Image copyrightRSPCAImage caption
The hedgehog had inflated to twice its natural size

An RSPCA spokesperson said balloon syndrome can be caused by a traumatic event, like an injury, or underlying infection, which releases gas into the cavity under the hedgehog's skin.

Treatment requires the skin to be punctured and a course of medication.

The large 1kg (2.2lb) hedgehog has been transferred to the RSPCA's Stapeley Grange Wildlife Centre in Nantwich, Cheshire, where he will be thoroughly examined under general anaesthetic and more air released.

He will be cared for at the centre until he is ready to be returned to the wild.